Li T et al, 2015: Supine versus Prone Position during Extracorporeal Shockwave Lithotripsy for Treating Distal Ureteral Calculi: A Systematic Review and Meta-Analysis.

Wednesday, 09 December 2015

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Li T, Gao L, Chen P, Bu S, Cao D, Yang L, Wei Q.
Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Chengdu, China.

Abstract

PURPOSE: We aimed at evaluating the efficacy of extracorporeal shockwave lithotripsy (SWL) for treating distal ureteral calculi performed in
supine vs. prone position.
MATERIALS AND METHODS: Eligible studies were identified by 2 reviewers using PubMed, Embase, and Web of Science databases. Outcomes included stone-free rate after the first and the final SWL session, the mean number of shocks per SWL session, the mean percentage of power used in the first SWL session, and the mean number of SWL sessions per patient.
RESULTS: Pooled data among the 647 included patients showed that supine SWL was associated with a significantly higher stone-free rate than prone SWL. This difference was consistent for both the first SWL session (OR 4.17; 95% CI 2.53-6.87; p < 0.00001) and the final session (OR 3.02; 95% CI 1.96-4.67; p < 0.00001). No differences in the mean number of shocks per SWL session, the mean percentage of power used in the first SWL session, and the mean number of SWL sessions per patient were observed between the positions. SWL complications were infrequent and the incidence was insufficient for further analysis.
CONCLUSION: SWL is safe and effective for the management of distal ureteral calculi, and supine SWL is more effective than prone SWL for achieving a stone-free status.

Urol Int. 2015 Sep 10. [Epub ahead of print]

Comments 1

Hans-Göran Tiselius on Wednesday, 09 December 2015 11:46

This report is a meta-analysis of treatment results following SWL with the patient in either supine or prone position (that is shockwaves directed from the back or from the abdominal side). Apparently the aim of the study was to get support for defining a standard approach for disintegration of stones in the distal ureter.

It is not evident how treatment in the prone position came to be the standard and recommended position for disintegration of stones in the distal ureter. When SWL initially was used for disintegration of distally located ureteral stones, SUPINE position was the rule [1-4]. I have personally used this patient position as my primary alternative when using HM3, MFL5000, SLX classic and SLX F2 devices. Having said that, it is of fundamental importance to state there is no EITHER/OR-position. To be successful with SWL of ureteral stones irrespective of location it is necessary to treat each patient individually. Accordingly, whereas the supine position is best for some patients the prone position will be best for others.

During every treatment it is absolutely necessary to have full and continuous control of the SW-path relative to the potential obstacles. For patients in prone position intestinal gas might be a problem that deserves special attention and possibly action. For patients in the supine position interference between the SW and skeletal structures needs attention.

One problem when scrutinizing the literature is that the definition of the distal ureter varies from one publication to another. In my own experience this part of the ureter extends from about 2 cm below the lower SI-joint to the orifice in the bladder. Proximally the mid ureter extends to a few cm above the upper SI-joint. Treatment of stones in the latter part of the ureter always has to be carried out in PRONE position [5-6].

The different skeletal structures to consider when treating distal stones in the SUPINE position are shown in the Figure below.

Haematuria during the treatment is an indicator of disintegration and the petechial bleedings a consequence of air bubbles in the coupling area. Despite an experience of more than 25 years of treating patients with SWL in the prone position, I have never encountered an intestinal perforation.

It is of note, however, that the optimal treatment position has to be decided not only from the anatomical landmarks, but also based on which lithotripter that is used and its angle of SW entrance.

References
1.Pettersson B,Tiselius HG (1988) Extracorporeal shock wave lithotripsy of proximal and distal ureteral stones. Eur Urol 14: 184-188.
2.Tiselius HG, Pettersson B,Andersson A (1989) Extracorporeal shock wave lithotripsy of stones in the middle part of the ureter. J Urol 141: 280-282.
3. Tiselius HG (1991) Anesthesia free in situ extracorporeal shock wave lithotripsy of ureteral stones. J Urol 146: 8-12.
4. Tiselius HG (1993) Anesthesia-free ESWL of distal ureteral stones without a ureteral catheter. J Endourol 7: 285-287.
5. Tiselius HG (2008) How efficient is extracorporeal lithotripsy with modern lithotripters for removal of ureteral stones? Journal of Endourology 22: 249-255.
6. Tiselius HG,Chaussy CG (2012) Aspects on how extracorporeal shockwave lithotripsy should be carried out in order to be maximally effective. Urological Research 40: 433-446.

It is not evident how treatment in the prone position came to be the standard and recommended position for disintegration of stones in the distal ureter. When SWL initially was used for disintegration of distally located ureteral stones, SUPINE position was the rule [1-4]. I have personally used this patient position as my primary alternative when using HM3, MFL5000, SLX classic and SLX F2 devices. Having said that, it is of fundamental importance to state there is no EITHER/OR-position. To be successful with SWL of ureteral stones irrespective of location it is necessary to treat each patient individually. Accordingly, whereas the supine position is best for some patients the prone position will be best for others.

During every treatment it is absolutely necessary to have full and continuous control of the SW-path relative to the potential obstacles. For patients in prone position intestinal gas might be a problem that deserves special attention and possibly action. For patients in the supine position interference between the SW and skeletal structures needs attention.

One problem when scrutinizing the literature is that the definition of the distal ureter varies from one publication to another. In my own experience this part of the ureter extends from about 2 cm below the lower SI-joint to the orifice in the bladder. Proximally the mid ureter extends to a few cm above the upper SI-joint. Treatment of stones in the latter part of the ureter always has to be carried out in PRONE position [5-6].

The different skeletal structures to consider when treating distal stones in the SUPINE position are shown in the Figure below.

Haematuria during the treatment is an indicator of disintegration and the petechial bleedings a consequence of air bubbles in the coupling area. Despite an experience of more than 25 years of treating patients with SWL in the prone position, I have never encountered an intestinal perforation.

It is of note, however, that the optimal treatment position has to be decided not only from the anatomical landmarks, but also based on which lithotripter that is used and its angle of SW entrance.

References
1.Pettersson B,Tiselius HG (1988) Extracorporeal shock wave lithotripsy of proximal and distal ureteral stones. Eur Urol 14: 184-188.
2.Tiselius HG, Pettersson B,Andersson A (1989) Extracorporeal shock wave lithotripsy of stones in the middle part of the ureter. J Urol  141: 280-282.
3. Tiselius HG (1991) Anesthesia free in situ extracorporeal shock wave lithotripsy of ureteral stones. J Urol 146: 8-12.
4. Tiselius HG (1993) Anesthesia-free ESWL of distal ureteral stones without a ureteral catheter. J Endourol  7: 285-287.
5. Tiselius HG (2008) How efficient is extracorporeal lithotripsy with modern lithotripters for removal of ureteral stones? Journal of Endourology  22: 249-255.
6. Tiselius HG,Chaussy CG (2012) Aspects on how extracorporeal shockwave lithotripsy should be carried out in order to be maximally effective. Urological Research  40: 433-446.

[img]http://storzmedical.com/images/blog/Li_T_2015.png[/img]

This report is a meta-analysis of treatment results following SWL with the patient in either supine or prone position (that is shockwaves directed from the back or from the abdominal side). Apparently the aim of the study was to get support for defining a standard approach for disintegration of stones in the distal ureter. It is not evident how treatment in the prone position came to be the standard and recommended position for disintegration of stones in the distal ureter. When SWL initially was used for disintegration of distally located ureteral stones, SUPINE position was the rule [1-4]. I have personally used this patient position as my primary alternative when using HM3, MFL5000, SLX classic and SLX F2 devices. Having said that, it is of fundamental importance to state there is no EITHER/OR-position. To be successful with SWL of ureteral stones irrespective of location it is necessary to treat each patient individually. Accordingly, whereas the supine position is best for some patients the prone position will be best for others. During every treatment it is absolutely necessary to have full and continuous control of the SW-path relative to the potential obstacles. For patients in prone position intestinal gas might be a problem that deserves special attention and possibly action. For patients in the supine position interference between the SW and skeletal structures needs attention. One problem when scrutinizing the literature is that the definition of the distal ureter varies from one publication to another. In my own experience this part of the ureter extends from about 2 cm below the lower SI-joint to the orifice in the bladder. Proximally the mid ureter extends to a few cm above the upper SI-joint. Treatment of stones in the latter part of the ureter always has to be carried out in PRONE position [5-6]. The different skeletal structures to consider when treating distal stones in the SUPINE position are shown in the Figure below. Haematuria during the treatment is an indicator of disintegration and the petechial bleedings a consequence of air bubbles in the coupling area. Despite an experience of more than 25 years of treating patients with SWL in the prone position, I have never encountered an intestinal perforation. It is of note, however, that the optimal treatment position has to be decided not only from the anatomical landmarks, but also based on which lithotripter that is used and its angle of SW entrance. References 1.Pettersson B,Tiselius HG (1988) Extracorporeal shock wave lithotripsy of proximal and distal ureteral stones. Eur Urol 14: 184-188. 2.Tiselius HG, Pettersson B,Andersson A (1989) Extracorporeal shock wave lithotripsy of stones in the middle part of the ureter. J Urol 141: 280-282. 3. Tiselius HG (1991) Anesthesia free in situ extracorporeal shock wave lithotripsy of ureteral stones. J Urol 146: 8-12. 4. Tiselius HG (1993) Anesthesia-free ESWL of distal ureteral stones without a ureteral catheter. J Endourol 7: 285-287. 5. Tiselius HG (2008) How efficient is extracorporeal lithotripsy with modern lithotripters for removal of ureteral stones? Journal of Endourology 22: 249-255. 6. Tiselius HG,Chaussy CG (2012) Aspects on how extracorporeal shockwave lithotripsy should be carried out in order to be maximally effective. Urological Research 40: 433-446. [img]http://storzmedical.com/images/blog/Li_T_2015.png[/img]

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